F you were bound from England to some town in South Wales, it was very awkward to have to leave your train on the banks of the Severn and make a voyage of more than two miles in a slow ferry-boat before you could take another train on the opposite shore. The Severn tides, too, were so erratic that there was never any knowing when the ferry-boat would be able to start. But that was what people had to put up with forty years ago. So the Great Western Railway Company, in 1871, decided to go under the fickle waters, as they found it so troublesome to go over them. A study of the bottom of the river made it clear that the tunnel they intended to make would have to slope downwards considerably from both ends, running level for a short distance only under the centre of the stream. This was because the waters, though shallow near either bank, are extremely deep in the middle, and to avoid this deeper part, the engineers had to burrow their way to a depth of one hundred and forty-five feet below high-water level at spring tide. The tunnel itself is four and a half miles long.

The work was begun in 1873. The slopes towards the river were made as gradual as possible, and the tunnel started from both ends at once. In order to find out what the soil and stone were like through which they would have to force their way, a shaft or pit, fifteen feet wide and two hundred feet deep, was dug on the western side of the river. From the bottom of this the boring or 'heading' (as the beginning of a tunnel is called) was worked east and west through rock and shale. Gunpowder was exploded in small holes drilled at frequent intervals to shatter this material; and when we remember that the 'heading' was only about six feet high and six feet wide we can imagine how uncomfortable this work must have been. Various kinds of drills have been invented for attacking stone, but the one most usually employed consists of a hard steel collar, round the edge of which black diamonds are fixed. There is no rock that can withstand this drill.

When the human moles, burrowing under the Severn from opposite sides, had got to within one hundred and thirty yards of each other, the drills of those in the western part suddenly broke through into the secret hiding-place of a great spring. The water gushed forth in cascades faster than the pumps could pump it out, and in twenty-four hours the 'heading' was filled with water. This was in October, 1879, and for two months all work was stopped. Then Sir John Hawkshaw was appointed chief engineer. With great difficulty larger pumps were set in action to draw the water out, and when this had been partly accomplished, it became necessary for some one to descend the shaft through thirty feet of water, grope his way for one thousand feet along the tunnel, and close a certain door which had been left open when the workmen fled in panic before the deluge. This door, together with two pipes which ran beneath it, allowed the passage of large quantities of water from under the river, the checking of which would enable the pumps to cope with the rest. A diver named Lambert undertook this task. He required twelve hundred feet of tubing to convey air to his helmet, and as this was more than one man could drag after him, two other divers were called upon to assist. One descended to the bottom of the shaft, while another walked up the 'heading' for five hundred feet, passing Lambert's air-tube along as the latter continued the terrible journey alone. Stumbling in the darkness over the scattered tools which the escaping workmen had thrown down, he arrived at last within a hundred feet of the door—only to find that he had not the strength to drag the air-hose any farther! Floating upwards in the water, it rubbed too hard against the ceiling of the tunnel to be pulled downwards and onwards. Lambert sat down, and, by a supreme effort, pulled it a few feet more. But the task was beyond his strength, and, greatly disappointed, he returned to the bottom of the shaft.

A few days later he tried again. This time no air-hose was used. Strapped on his back he carried a vessel filled with condensed oxygen gas, which he could admit to the helmet in small quantities at will. Groping his way once more along the narrow, water-choked passage, he at last reached the door. Passing through to the other side he felt for the open end of one of the pipes, and turned the screws of its valve. Then, stepping back, he shut the door behind him. All that now remained to be done was to seal the second pipe. This had what is called a sluice valve, and Lambert had been instructed to turn the screw which closed it round and round, until he found he could turn it no farther; when that was done, he would know that it was shut. It took some time, but it was accomplished at last, and the triumphant diver returned to the upper air. He had been absent one hour and eighteen minutes.

Lambert had done well, and all were ready to acknowledge his great courage; but the water, strange to say, remained abundant, and it was only after still further increasing the size of the pumps that it was at last got rid of. Then the secret came out: no one had told Lambert that the sluice valve had a left-handed screw, and that, therefore, to close it he would have to turn it in the opposite direction to the usual one. So all his heroic labour was expended on opening the valve to its fullest extent, and thwarting the purpose for which he had undertaken such a perilous duty.

This spring proved to be the greatest enemy the engineers had. But on one occasion the sea itself made an attack upon them. A tidal wave burst over the Severn's banks one night, and, rushing in a volume five feet high, entered the workmen's cottages, and rose above the beds on which their children were asleep. They were only saved by being lifted on to tables and shelves. Then the great mass of water rolled on, to fall in a huge torrent down the tunnel shaft. At the bottom eighty-three men were at work. They escaped by running up the sloping tunnel and climbing a wooden stage or platform at the far end. The water rose to within eight feet of the tunnel-roof. As soon as the mouth of the shaft could be reached from above, a small boat was lowered, and upon the gloomy subterranean river a party of rescuers rowed in search of the imprisoned men. A huge timber, stretched from side to side of the tunnel, soon barred the boat's progress, and it became necessary to return to the shaft for a saw to cut it in two. This they dropped overboard before accomplishing their purpose, and had to wait while another was obtained. Eventually, however, the men were reached and removed from their terrible prison.

But through danger and difficulty alike, the Severn Tunnel was pushed on with, reaching completion in 1886—fourteen years after its beginning—and was opened for passenger traffic on December 1st, in that year.

John Lea.